1. Field of the Invention
The present invention relates to a detector of a liquid consumption condition that can detect a consumption condition of a liquid such as an ink, by detecting changes in an acoustic impedance, particularly by detecting changes in a resonance frequency.
2. Description of the Related Art
In an ink jet recording apparatus, an ink jet recording head having: a pressure generating means that can pressurize a pressure generating chamber; and a nozzle that can jet pressurized ink as an ink drop, is mounted on a carriage. In the ink jet recording apparatus, ink in an ink tank continues to be fed to the recording head via a flow path, so as to permit continuous printing. The ink tank is generally structured as a removable cartridge that can be simply exchanged by a user when the ink is consumed.
Conventionally, as an ink consumption control method of an ink cartridge, a method for totalizing the number of ink drops jetted by the recording head and the ink amount sucked at the maintenance step by means of some software and controlling the ink consumption from calculation; and a method for attaching electrodes for detecting a liquid level to the ink cartridge, detecting the point of time when the ink is actually consumed by a predetermined amount, thereby controlling the ink consumption; are known.
The method for totalizing the number of jetted ink drops and the sucked ink amount by the software and controlling the ink consumption from calculation has an advantage in cost, because the method needs no special detector. However, in the method, some errors may be caused by difference of printing manners that can be selected by the user. In addition, larger errors may be generated when the same cartridge is refitted. Furthermore, pressure in the ink cartridge and ink viscosity may be varied with a use environment (for example, extremely high or low room temperature), or an elapsed time after opening the ink cartridge, so that unnegligible errors may be caused between the ink consumption from calculation and the actual consumption.
On the other hand, the method of controlling the point of time of ink consumption by the electrodes can detect the actual amount of ink consumption at a certain point, so that it can control the residual quantity of ink with high reliability. However, the ink has to be conductive so as to detect the ink level, accordingly the kind of ink to be used (detected) is limited. Further, a problem arises that the liquid tight structure between the electrodes and the ink cartridge is complicated. Furthermore, as a material of the electrodes, a noble metal which is enough conductive and highly corrosion-resistant is ordinarily used, so that a problem also arises that manufacturing cost of an ink cartridge is increased. Furthermore, two electrodes must be mounted, so that many manufacturing steps are required and the manufacturing cost is more increased.
An object of the present invention is to provide a detector of liquid consumption condition that can effectively make good use of the detection of the liquid consumption condition.
The invention is a detector of liquid consumption condition comprising: a vibrating part that can vibrate relatively to a containing space that can be filled and refilled with a liquid, at least a portion of the vibrating part being exposed to the containing space; a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; and a liquid consumption condition detecting part that can detect a liquid consumption condition based on the counter electromotive force signal from the piezoelectric device; wherein the containing space can contain only a predetermined volume of the liquid, and the vibrating part is provided in a vicinity of a liquid surface in the containing space when the containing space contains the predetermined volume of the liquid.
According to the feature, a liquid-full condition of the containing space can be detected highly reliably. This feature is very effective for a liquid replenishment operation to fill the containing space to a liquid-full condition.
Alternatively, the invention is a detector of liquid consumption condition comprising: a vibrating part that can vibrate relatively to a containing space that can be filled and refilled with a liquid, at least a portion of the vibrating part being exposed to the containing space; a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; a second vibrating part that can vibrate relatively to the containing space, at least a portion of the second vibrating part being exposed to the containing space; a second piezoelectric device that can cause the second vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the second vibrating part; and a liquid consumption condition detecting part that can detect a liquid consumption condition based on the counter electromotive force signal from at least one of the piezoelectric devices; wherein the containing space can contain only a predetermined volume of the liquid, the vibrating part and the piezoelectric device are provided in a vicinity of a liquid surface in the containing space when the containing space contains the predetermined volume of the liquid, and the second vibrating part and the second piezoelectric device are provided in a vicinity of a liquid surface in the containing space when the liquid is exhausted from the containing space.
According to the feature, a liquid-full condition and a liquid-end condition of the containing space can be detected highly reliably. This feature is very effective for a liquid replenishment operation to fill the containing space to a liquid-full condition after a liquid-end condition has been detected.
Alternatively, the invention is a detector of liquid consumption condition comprising: a vibrating part that can vibrate relatively to a containing space that can be filled and refilled with a liquid, at least a portion of the vibrating part being exposed to the containing space; a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; a second vibrating part that can vibrate relatively to the containing space, at least a portion of the second vibrating part being exposed to the containing space; a second piezoelectric device that can cause the second vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the second vibrating part; and a liquid consumption condition detecting part that can detect a liquid consumption condition based on the counter electromotive force signal from at least one of the piezoelectric devices; wherein the vibrating part and the piezoelectric device are provided in a vicinity of and higher than a predetermined level in the containing space, and the second vibrating part and the second piezoelectric device are provided in a vicinity of and lower than the predetermined level in the containing space.
According to the feature, it can be detected highly reliably whether a liquid surface level in the containing space exists in a predetermined area defined by the two vibrating parts or not. This feature is very effective for maintaining a liquid surface level at a substantially fixed point to maintain a liquid-head pressure at a substantially fixed point.
For example, the liquid consumption condition detecting part may be adapted to measure a frequency of the counter electromotive force signal. Thus, the liquid consumption condition can be detected simply and precisely because the frequency of the counter electromotive force signal corresponds to the resonance frequency of the object or objects in the containing space.
In detail, the liquid consumption condition detecting part may have a counter that can count the number of vibrations in the counter electromotive force signal for a predetermined time, and the liquid consumption condition detecting part may be adapted to measure the frequency of the counter electromotive force signal based on the number counted by the counter.
Alternatively, the liquid consumption condition detecting part may have a clock-counter that can measure a time for which the counter electromotive force signal vibrates a predetermined number of times, and the liquid consumption condition detecting part may be adapted to measure the frequency of the counter electromotive force signal based on the time measured by the clock-counter.
In addition, preferably, the portion of the vibrating part exposed to the containing space has a symmetric shape as seen from a side of the containing space. Furthermore, preferably, the piezoelectric device is fixed to a side of the vibrating part opposite to the containing space at a substantially central position of the portion of the vibrating part exposed to the containing space.
In particular, it is very preferable that the portion of the vibrating part exposed to the containing space has a circular shape as seen from the side of the containing space.
In addition, preferably, the piezoelectric device is adapted to vibrate in a direction substantially perpendicular to the portion of the vibrating part exposed to the containing space.
In addition, preferably, the portion of the vibrating part exposed to the containing space has a liquid-philic characteristic with respect to the liquid. In the case, it is not easy for the liquid to stick the portion, so that a mistake in detection, which may be caused by sticking of the liquid to the portion, can be prevented.
In addition, preferably, a cavity part having a liquid-philic characteristic with respect to the liquid is provided in such a manner that the cavity part surrounds the portion of the vibrating part exposed to the containing space. In the case, a condition wherein the liquid exists in the cavity and doesn""t exist outside the cavity can be set as a threshold condition for judging the liquid consumption condition. In the case, precision of the judgement of the liquid consumption condition can be improved.
A liquid container (for example, an ink cartridge) including a detector of liquid consumption condition with at least one above feature and a wall part defining the containing space for containing the liquid: should be protected by the application. In addition, a liquid container without the liquid consumption condition detecting part (a liquid container wherein the liquid consumption condition detecting part is arranged outside the liquid container) should be protected by the application as well.
That is, it is intended to protect a liquid container comprising: a wall part defining a containing space that can contain a liquid in a refillable manner; a vibrating part that can vibrate relatively to the containing space, at least a portion of the vibrating part being exposed to the containing space; and a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; wherein the containing space can contain only a predetermined volume of the liquid, and the vibrating part is provided in a vicinity of a liquid surface in the containing space when the containing space contains the predetermined volume of the liquid.
It is also intended to protect a liquid container comprising: a wall part defining a containing space that can contain a liquid in a refillable manner; a vibrating part that can vibrate relatively to the containing space, at least a portion of the vibrating part being exposed to the containing space; a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; a second vibrating part that can vibrate relatively to the containing space, at least a portion of the second vibrating part being exposed to the containing space; and a second piezoelectric device that can cause the second vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the second vibrating part; wherein the containing space can contain only a predetermined volume of the liquid, the vibrating part and the piezoelectric device are provided in a vicinity of a liquid surface in the containing space when the containing space contains the predetermined volume of the liquid, and the second vibrating part and the second piezoelectric device are provided in a vicinity of a liquid surface in the containing space when the liquid is exhausted from the containing space.
It is also intended to protect a liquid container comprising: a wall part defining a containing space that can contain a liquid in a refillable manner; a vibrating part that can vibrate relatively to the containing space, at least a portion of the vibrating part being exposed to the containing space; a piezoelectric device that can cause the vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the vibrating part; a second vibrating part that can vibrate relatively to the containing space, at least a portion of the second vibrating part being exposed to the containing space; and a second piezoelectric device that can cause the second vibrating part to vibrate based on a driving signal and that can generate a counter electromotive force signal by a vibration of the second vibrating part; wherein the vibrating part and the piezoelectric device are provided in a vicinity of and higher than a predetermined level in the containing space, and the second vibrating part and the second piezoelectric device are provided in a vicinity of and lower than the predetermined level in the containing space.
The liquid container may further comprise a liquid consumption condition detecting part that can detect a liquid consumption condition based on the counter electromotive force signal from the piezoelectric device.
In the case, preferably, the liquid container may further comprise a storage that can store the liquid consumption condition detected by the liquid consumption condition detecting part.
In addition, preferably, a region of the wall part in a vicinity of the portion of the vibrating part exposed to the containing space has a liquid-philic characteristic with respect to the liquid.
Especially, if a cavity part having a liquid-philic characteristic with respect to the liquid is provided in such a manner that the cavity part surrounds the portion of the vibrating part exposed to the containing space, it is preferable that a region of the wall part adjacent to the cavity part has a liquid-philic characteristic with respect to the liquid. In the case, sticking of the liquid, which may cover the whole cavity, can be prevented.
On the contrary, even if a cavity part having a liquid-philic characteristic with respect to the liquid is provided in such a manner that the cavity part surrounds the portion of the vibrating part exposed to the containing space, it may be preferable that a region of the wall part adjacent to the cavity part has a liquid-phobic characteristic with respect to the liquid, in view of precision of the judgement of the liquid consumption condition.
A method of manufacturing a liquid container having such a liquid-philic portion may comprise: a liquid-philic-part forming step of structuring the portion of the vibrating part exposed to the containing space as a part having a liquid-philic characteristic with respect to the liquid; and a mounting step of attaching the liquid consumption condition detecting part to the wall part, after the liquid-philic-part forming step.
Alternatively, a method of manufacturing a liquid container having such a liquid-philic portion may comprise: a mounting step of attaching the liquid consumption condition detecting part to the wall part; and a liquid-philic-part forming step of providing a liquid-philic characteristic with respect to the liquid for the portion of the vibrating part exposed to the containing space, after the mounting step.
A liquid consuming apparatus (for example, an ink-jet recording apparatus) including a liquid container with at least one above feature and a liquid consuming body that can consume the liquid contained in the liquid container, the liquid consuming body being connected to the liquid container: should be protected by the application as well.
In the case, preferably, the liquid consuming apparatus may further comprise: a liquid replenishing unit that can replenish the containing space in the liquid container with the liquid; and a replenishment controller that can control the liquid replenishing unit based on the liquid consumption condition detected by the liquid consumption condition detecting part.
In addition, preferably, the liquid consuming apparatus may further comprise: a controlling circuit that can control a liquid consuming operation of the liquid consuming body, based on the liquid consumption condition detected by the liquid consumption condition detecting part.
Alternatively, preferably, the liquid consuming apparatus may further comprise: a storage that can store the liquid consumption condition detected by the liquid consumption condition detecting part; and a controlling circuit that can control a liquid consuming operation of the liquid consuming body, based on the liquid consumption condition stored by the storage.
Furthermore, a controlling unit that can control a detector of liquid consumption condition with at least one above feature, that can give the driving signal to the piezoelectric device and that can cause the liquid consumption condition detecting part to detect the liquid consumption condition: should be protected by the application as well.
The above controlling unit and one or more components thereof can be materialized by a computer system. A program for materializing the controlling unit or one or more components thereof in the computer system, and a storage medium storing the program capable of being read by a computer, should be protected by the application as well.
The storage medium may be not only a substantial object such as a floppy disk or the like, but also a network for transmitting various signals.